X ( 2 , 8 , 3 , 7 ) X ( 4 , 2 , 5 , 1 ) X ( 6 , 15 , 7 , 16 ) X ( 8 , 4 , 9 , 3 ) X ( 10 , 22 , 11 , 21 ) X ( 12 , 17 , 13 , 18 ) X ( 14 , 5 , 15 , 6 ) X ( 16 , 13 , 17 , 14 ) X ( 18 , 11 , 19 , 12 ) X ( 20 , 10 , 21 , 9 ) X ( 22 , 20 , 1 , 19 ) {\displaystyle X(2,8,3,7)X(4,2,5,1)X(6,15,7,16)X(8,4,9,3)X(10,22,11,21)X(12,17,13,18)X(14,5,15,6)X(16,13,17,14)X(18,11,19,12)X(20,10,21,9)X(22,20,1,19)}